[vpn-help] compression support

[Gerd Röthig]

Dear Matthew, dear all,

doing some search in the net, I came across the VPN-Help mailinglist and
found that compression support was already discussed back in 2007:

Thorsten,

Thanks for reminding me of this. I will need to go back and check but 
believe there are a few things missing in the policy generation code 
that prevents compression from working properly. It should be grayed 
back out until I get that sorted. IPcomp ( compression ) AH as well as 
transport mode support for AH/ESP was added to the IPsec Daemon during 
the 2.0.0 development cycle but options never fully made it into the 
Site Configuration dialogs. If compression will help you, I can look 
into reviving this support for the 2.1.x branch.

As for LZS, the algorithms are patent encumbered. Here is the text 
included in RFC 2395 ...

1.3 Licensing

    Hi/fn, Inc. holds patents on the LZS algorithm. Licenses for a
    reference implementation are available for use in IPPCP, IPSec, TLS
    and PPP applications at no cost.  Source and object licenses are
    available on a non-discriminatory basis. Hardware implementations are
    also available.  For more information, contact Hi/fn at the address
    listed with the authors' addresses.

... which makes me believe that it would be possible for Shrew Soft to 
obtain a license to use an LZS reference implementation at no cost since 
we will be using it with IPsec. I tried to email the addresses listed in 
the RFC several times but have never had a reply. There is an additional 
disclosure made by a hifn representative here ...

http://www.ietf.org/ietf/IPR/hifn-ipr-multiple-rfcs.txt

... which makes me think I may need to snail mail them something. I just 
know that I haven't had much time to look into it. Maybe one of the 
other non-technical Shrew Soft guys can tackle this for us. They own 
suits and fancy degrees which surely gives them an advantage :) I will 
keep you posted.

Thanks,

-Matthew

As we now have 2013 and there is still no LZW support available in Shrew
Soft VPN Client, please kindly allow me to ask how the current state is with
regards to compression support.

Thank you very much in advance and kind regards,

Gerd